Prime Minister Malcolm Turnbull calls on Australians to support same-sex marriage in the upcoming postal survey as thousands pack out Sydney's CBD to rally for change in what organisers claim was the largest LGBTI demonstration in Australian history.

Australians are more interested in the personal than the politics when it comes to the country's leaders, with searches about Malcolm Turnbull's Donald Trump impersonation and Bill Shorten's wife and net worth ranking highly on Google Trends.

Minutes after the High Court approved the postal survey on same sex marriage, Opposition Leader Bill Shorten asked Malcolm Turnbull whether the Prime Minister would accept an invitation to campaign together for a Yes vote.

A year ago, Malcolm Turnbull pledged to the WA Liberal faithful he would introduce a GST floor to return more money to the State. With nothing eventuating, the party is downplaying hopes of any significant announcement this weekend.

Prime Minister Malcolm Turnbull is at odds with the federal Liberal Party president over the Coalition's chances at the next election after trailing Labor in the last 18 opinion polls conducted by Newspoll.

After spending a day touring the Snowy Hydro Scheme, Prime Minister Malcolm Turnbull backs away from an investment in coal power plants that could appease some in his party room hesitant to support a clean energy target.

The cost of Government IT systems has jumped to nearly $10 billion — despite not always resulting in better outcomes for the public — because public servants prefer old, familiar solutions to newer and more innovative ones, according to a report.

Malcolm Turnbull says he cannot remember anyone but Tony Abbott being "too drunk to get into the chamber", after Mr Abbott revealed he missed a crucial 2009 vote because he was out cold after a boozy dinner with Peter Costello.